<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>三栏布局</title>
    <style>
        .container{
            width:800px;
            height: 200px;
        }
        .left{
            height: 100%;
            float: left;
            width: 200px;
            background-color: lightgreen;
        }
        .right{
            height: 100%;
            float: right;
            height:100%;
            width: 220px;
            background-color: aqua
        }
        .middle{
            margin: 0 220px 0 200px;
            height: 100%;
            background-color: blue;;
        }
    </style>
</head>
<body>
    <div class="container">
        
        <div class="left">left</div>
        <div class="right">right</div>
        
        <div class="middle">middle</div>
        
    </div>
</body>
</html>